A 3D printable concrete material, method of making and method of use

Abstract

The application relates to the technical field of concrete, and particularly discloses a 3D-printable concrete material, a preparation method and a use method, which comprises the following components in proportion by weight: aluminate cement 470-490 parts; silica fume 70-90 parts; fine aggregate 790-810 parts; water reducing agent 2-5 parts; and retarder 1-3 parts. The concrete material can realize 3D printing and can well inherit the high-temperature resistance and corrosion resistance of aluminate cement. In addition, the 3D printing technology is applied to the production of aluminate cement refractory materials, which can provide great theoretical basis and technical support for the production and application of refractory materials with higher precision requirements and more complex modeling requirements.

Description

Technical Field

[0001] This invention relates to the field of concrete technology, and more specifically, to a 3D-printable concrete material, its preparation method, and its application method. Background Technology

[0002] 3D printing technology, as a core technology of the Third Industrial Revolution, has become a hot topic, gradually moving from the experimental field into the industrial sector. Clay materials, with their advantages of high temperature resistance, corrosion resistance, high strength, and high hardness, have always attracted widespread attention and play a role in various industrial fields as an excellent refractory material. Clay 3D printing technology not only breaks the limitations of traditional ceramic material processing techniques but also provides more possibilities for the efficient production of various uniquely shaped refractory products. However, with the mass production and application of refractory materials, the high price of clay has become its biggest drawback.

[0003] Chinese patent application number 201710295800.4 discloses a casting method for making handicrafts using 3D printing. This invention uses photographic technology to capture images, which are then transmitted to a computer to convert them into processing drawings. These drawings are then input into a 3D printer, which uses ceramic powder refractory composite material as "ink" to 3D print the shell. After printing, the material is sintered and solidified, and then molten material is poured in. Once formed, the shell is broken to obtain the finished product. Compared to traditional lost-wax casting, this invention significantly reduces workload and has a faster production cycle, meeting the need for people to create finished products from images they see at any time. However, in practical applications, the conversion from two-dimensional to three-dimensional images during photographic capture makes it difficult to guarantee the forming accuracy of the finished product. Secondly, the printing material is ceramic powder; due to limitations in material supply and cost, this invention is limited to printing small handicrafts and is difficult to apply on a large scale to the industrial field to achieve large-scale production of industrial refractory products.

[0004] Therefore, it is of great significance to find a 3D printing refractory material that is both heat-resistant and corrosion-resistant, and relatively inexpensive to meet the needs of mass production. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a 3D-printable concrete material, its preparation method, and its application method. The concrete material of this invention can be 3D printed and also inherits the high-temperature resistance and corrosion resistance properties of aluminate cement. Furthermore, applying 3D printing technology to the production of aluminate cement refractory materials will provide significant theoretical basis and technical support for the production and application of refractory materials with higher precision requirements and more complex shapes.

[0006] The solution adopted by this invention to solve the technical problem is: on the one hand: This invention provides a 3D-printable concrete material, comprising the following components by weight: 470-490 parts of aluminate cement; 70-90 parts silica fume; 790-810 parts of fine aggregate; 2-5 parts water-reducing agent; 1-3 parts of retarder.

[0007] In some possible implementations, the Al2O3 content in the aluminate cement is not less than 50%.

[0008] In some possible implementations, the particle size of the silica fume is 0.2 μm to 35 μm.

[0009] In some possible embodiments, the fine aggregate has a particle size of 0.15~0.3 mm, a fineness modulus of 1.6~2.2, and a bulk density of 1610~1630 kg / m³. 3 .

[0010] In some possible implementations, the water-reducing agent is a polycarboxylate-based water-reducing agent with a water reduction rate greater than 30% and a solid content less than 40%.

[0011] In some possible implementations, the retarder is one or more of citric acid retarder, boric acid retarder, and sodium gluconate retarder.

[0012] In some possible embodiments, the aluminate cement is pure calcium aluminate cement or a pure calcium aluminate cement mixture with added α-Al2O3.

[0013] on the other hand: This invention provides a method for preparing 3D-printable concrete material as described above, specifically including the following steps: Step S1: Mix aluminate cement, silica fume, and fine aggregate to obtain a mixture. The water-reducing agent is mixed with water to obtain a mixed slurry; Mix the retarder with water to obtain a retarder solution; Step S2: Mix the mixture, slurry, and retarder solution to obtain a 3D-printable concrete material.

[0014] In some possible implementations, the mass ratio of the water-reducing agent to water is 8~22:108; The mass ratio of the retarder to water is 1~3:72.

[0015] On the other hand: This invention provides a method for using a 3D-printable concrete material as described above, or a concrete material prepared using the method described above. Specifically, the concrete material is poured into a 3D printer for printing. During 3D printing, the nozzle diameter is 1-3 cm, and the extrusion speed is 0.3-0.4 m / s. 3 / h, horizontal printing speed 250~290m / h.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The concrete material provided by this invention uses aluminate cement with an Al2O3 content of not less than 50%, which can be formulated with refractory aggregates, powders, and some admixtures to form refractory materials. It exhibits high fluidity, high-temperature resistance, and abrasion resistance. Furthermore, when used in conjunction with water-reducing agents and retarders, the reaction rate of the cementitious materials can be appropriately controlled while ensuring the concrete's strength and high-temperature resistance. This allows for a more appropriate and controllable hydration rate in the cementitious system, thereby ensuring that the special high-temperature resistant concrete provided by this invention can be better implemented using 3D printing technology. Attached Figure Description

[0017] Figure 1 The concrete prepared using Example 2 of this invention; Figure 2 This is a schematic diagram comparing the performance of printed concrete and ordinary concrete after high temperature. Detailed Implementation

[0018] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. For example, multiple positioning posts refer to two or more positioning posts. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0019] The present invention will now be described in detail.

[0020] on the one hand: This invention provides a 3D-printable concrete material, comprising the following components by weight: 470-490 parts of aluminate cement; 70-90 parts silica fume; 790-810 parts of fine aggregate; 2-5 parts water-reducing agent; 1-3 parts of retarder.

[0021] Specifically, aluminate cement, as a cementing material, mainly plays the role of coating aggregates and ensuring the strength, fire resistance and corrosion resistance of hardened concrete. Silica fume can fill the pores between cement particles and react with hydration products to form a gel. It can also react with the alkaline material magnesium oxide to form a gel, which can significantly improve the compressive strength, flexural strength, impermeability, corrosion resistance, impact resistance and wear resistance.

[0022] In some possible embodiments, the content of Al2O3 in the aluminate cement is not less than 50%, preferably 480-488 parts, more preferably 480-482 parts; the present invention does not have a special limitation on the source of aluminate cement, and commercially available products well known to those skilled in the art can be used.

[0023] In some possible implementations, the particle size of the silica fume is 0.2 μm to 35 μm; Preferably, the particle size of the silica fume is 0.2μm~25μm, and most preferably 0.5μm~10μm.

[0024] The present invention does not specifically limit the source of the silica fume; any commercially available product well known to those skilled in the art can be used.

[0025] In some possible embodiments, the fine aggregate has a particle size of 0.15~0.3 mm, a fineness modulus of 1.6~2.2, and a bulk density of 1610~1630 kg / m³. 3 ; Preferably, the fine aggregate is 795-805 parts, more preferably 798-802 parts.

[0026] The preferred particle size of the fine aggregate is 0.20~0.25 mm, and the most preferred is 0.22~0.23 mm; The fineness modulus of the fine aggregate is preferably 1.6 to 2.0, and most preferably 1.8; The bulk density of the fine aggregate is preferably 1615~1625 kg / m³. 3 The optimal value is 1620 kg / m³. 3 .

[0027] Furthermore, in this invention, when the particle size of the fine aggregate does not meet the required particle size, fineness modulus, or bulk density, it is preferable to crush the fine aggregate.

[0028] It should be noted that, in this invention, the fine aggregate is preferably one or more of quartz sand and river sand, more preferably quartz sand. In this invention, the fine aggregate acts as a skeleton or filler in concrete.

[0029] In some possible embodiments, the water-reducing agent is a polycarboxylate-based water-reducing agent with a water reduction rate greater than 30% and a solid content less than 40%; preferably, the water-reducing agent is 2 to 4 parts, more preferably 2 to 3 parts; in this invention, the water-reducing agent can reduce the amount of water used, thereby improving the density and hardness of the prepared concrete and increasing its fluidity.

[0030] In some possible implementations, the retarder is one or more of citric acid retarder, boric acid retarder, and sodium gluconate retarder; Preferably, the retarder is a citric acid retarder; This invention does not specifically limit the source of the citric acid retarder; any commercially available product well-known to those skilled in the art can be used. In this invention, the citric acid retarder can appropriately regulate the reaction rate of the cementitious material, achieving a suitable and controllable hydration rate in the cementitious system, thereby improving the plasticity of the cementitious material and ensuring its 3D printing performance.

[0031] In some possible embodiments, the aluminate cement is pure calcium aluminate cement or a pure calcium aluminate cement mixture with added α-Al2O3.

[0032] on the other hand: This invention provides a method for preparing 3D-printable concrete material as described above, specifically including the following steps: Step S1: Mix aluminate cement, silica fume, and fine aggregate to obtain a mixture. This invention does not impose special limitations on the mixing operation of the aluminate cement, silica fume, and fine aggregate; any technical solution well-known to those skilled in the art for preparing the mixture can be used. In this invention, the mixing of the aluminate cement, silica fume, and fine aggregate is preferably carried out under stirring conditions. This invention does not impose special limitations on the stirring rate and time, as long as the components are mixed uniformly.

[0033] The water-reducing agent is mixed with water to obtain a mixed slurry; The mass ratio of the water-reducing agent to water is 8~22:108, more preferably (1~15):108, and most preferably (10~12):108.

[0034] This invention does not impose any particular limitation on the mixing operation of the water-reducing agent and water; any mixing method well known to those skilled in the art can be used. In this invention, the mixing of the water-reducing agent and water is preferably carried out under stirring conditions. This invention does not impose any particular limitation on the stirring rate and time, as long as the components are mixed evenly.

[0035] Mix the retarder with water to obtain a retarder solution; In this invention, the mass ratio of the retarder to water is preferably 1~3:72, more preferably (1~2):72, and most preferably 1:72.

[0036] This invention does not impose any particular limitations on the mixing operation of the retarder and water; any mixing method well known to those skilled in the art can be used. In this invention, the mixing of citric acid and water is preferably carried out under stirring conditions. This invention does not impose any particular limitations on the stirring rate and time, as long as the components are mixed uniformly.

[0037] Step S2: After obtaining the mixture, the slurry, and the retarder solution, the present invention mixes the mixture, the slurry, and the retarder solution to obtain a mixture. The present invention does not have any particular limitation on the mixing method of the mixture, the slurry, and the retarder solution; any mixing method well known to those skilled in the art can be used.

[0038] In this invention, the mixing of the mixture, the mixed slurry, and the retarder solution preferably includes: pre-stirring the mixture, and then sequentially adding the mixed slurry and the retarder solution. In this invention, the mixing of the mixture, the mixed slurry, and the cellulose solution is preferably carried out in a stirred tank.

[0039] In this invention, the pre-stirring rate is not specifically limited; the pre-stirring time is preferably 100-140 s, more preferably 110-130 s, and most preferably 120 s. In this invention, the pre-stirring is to ensure that the components of the mixture are mixed evenly.

[0040] In this invention, the mixed slurry is preferably added uniformly to the pre-mixed mixture within 10 seconds for stirring. In this invention, the stirring time is preferably 400-800 seconds, more preferably 500-700 seconds, and most preferably 600 seconds.

[0041] In this invention, the retarder solution is preferably added uniformly to the mixture of the mixed materials and the mixed slurry within 10 seconds and then stirred. In this invention, the stirring time is preferably 160-200 seconds, more preferably 170-190 seconds, and most preferably 180 seconds.

[0042] The preparation method provided by the present invention can fully utilize the water-reducing effect of the water-reducing agent by stirring the mixture and the slurry, and the addition of the retarder solution can prolong the setting time of the material and improve the plasticity of the material. Under stirring conditions, the raw materials are uniformly mixed during the stepwise addition process, resulting in consistent performance.

[0043] On the other hand: This invention provides a method for using a 3D printable concrete material or a concrete material prepared by the above-described preparation method. Specifically, the concrete material is poured into a 3D printer for printing. During 3D printing, the nozzle diameter is 1-3 cm, the extrusion speed is 0.3-0.4 m³ / h, and the horizontal printing speed is 250-290 m / h.

[0044] Furthermore, it is preferable that the nozzle diameter is 2cm, the extrusion speed is 0.35~0.38m3 / h, and the horizontal printing speed is 260~285m / h.

[0045] This invention does not impose any special limitations on the 3D printing equipment; any 3D printing equipment well known to those skilled in the art can be used.

[0046] The printing parameters of the method provided by this invention can be matched with the 3D printable special high-temperature resistant concrete described in the above technical solution or the 3D printable special high-temperature resistant concrete prepared by the preparation method described in the above technical solution, thereby realizing the 3D printing of 3D printable special high-temperature resistant concrete.

[0047] Example 1: A method for preparing a special high-temperature resistant concrete material that can be 3D printed specifically includes the following steps: (1) By weight, 480 parts of aluminate cement with an Al2O3 content of not less than 50%, 80 parts of silica fume with a particle size of 6μm~8μm, and a bulk density of 1620 kg / m³. 3 800 parts of quartz sand were mixed to obtain a mixture. By weight, 10 parts of water-reducing agent are mixed with 108 parts of water (the mass ratio of water-reducing agent to water is 10:108) to obtain a mixed slurry. By weight, 1 part of citric acid retarder and 72 parts of water are mixed to obtain a citric acid solution.

[0048] (2) The resulting mixture is pre-stirred in a mixing tank for 120 seconds; Then, the resulting slurry is added uniformly to the pre-mixed mixture within 10 seconds and stirred for 600 seconds. The obtained citric acid solution is added uniformly to the mixture of the mixed material and the mixed slurry within 10 seconds and stirred for 180 seconds to obtain the 3D printable concrete material.

[0049] Example 2: A method for using a special high-temperature resistant concrete material that can be 3D printed involves 3D printing the concrete material obtained above, setting the nozzle diameter to 2cm, and setting the printing parameters of the printing equipment as follows: extrusion speed of 0.09m / s². 3 The horizontal printing speed is 180 m / h, and the material pump speed to the storage hopper is matched with the printing speed before printing; the printed product is as follows: Figure 1 .

[0050] pass Figure 1 Therefore, the high-temperature resistant special concrete of this invention can be extruded from cement and has excellent constructability, meeting the material performance requirements of 3D printed concrete. Figure 2 It can be seen that the compressive strength of the 3D-printable high-temperature resistant special concrete invented in this application is much higher than that of 3D-printed ordinary silicate cement concrete at various temperatures, indicating that the concrete invented in this application has good high-temperature resistance.

[0051] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A 3D-printable concrete material, characterized in that, By weight, it includes the following components: 470-490 parts of aluminate cement; 70-90 parts silica fume; 790-810 parts of fine aggregate; 2-5 parts water-reducing agent; 1-3 parts of retarder.

2. The 3D-printable concrete material according to claim 1, characterized in that, The aluminate cement contains no less than 50% Al2O3.

3. The 3D-printable concrete material according to claim 1, characterized in that, The particle size of the silica fume is 0.2μm~35μm.

4. The 3D-printable concrete material according to claim 1, characterized in that, The fine aggregate has a particle size of 0.15~0.3 mm, a fineness modulus of 1.6~2.2, and a bulk density of 1610~1630 kg / m³. 3 .

5. The 3D-printable concrete material according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate-based water-reducing agent with a water reduction rate greater than 30% and a solid content less than 40%.

6. The 3D-printable concrete material according to claim 1, characterized in that, The retarder is one or more of citric acid retarder, boric acid retarder, and sodium gluconate retarder.

7. A 3D-printable concrete material according to claim 2, characterized in that, The aluminate cement is pure calcium aluminate cement or a pure calcium aluminate cement mixture with added α-Al2O3.

8. A method for preparing a 3D-printable concrete material as described in any one of claims 1-6, characterized in that, Specifically, the following steps are included: Step S1: Mix aluminate cement, silica fume, and fine aggregate to obtain a mixture. The water-reducing agent is mixed with water to obtain a mixed slurry; Mix the retarder with water to obtain a retarder solution; Step S2: Mix the mixture, slurry, and retarder solution to obtain a 3D-printable concrete material.

9. The preparation method according to claim 8, characterized in that, The mass ratio of the water-reducing agent to water is 8~22:108; The mass ratio of the retarder to water is 1~3:

72.

10. A method of using a 3D-printable concrete material according to any one of claims 1-8 or a concrete material prepared by the preparation method according to claim 9, characterized in that, Specifically, this refers to pouring concrete material into a 3D printer for printing. During 3D printing, the nozzle diameter is 1~3cm, the extrusion speed is 0.3~0.4m3 / h, and the horizontal printing speed is 250~290m / h.

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